Molecular markers
Polymerase chain reaction

Topic Completed: 1 January 2010

Minor changes: 15 February 2019

Copyright: 2008-2018,, Inc.

PubMed Search: Polymerase chain reaction[TI] history free full text[sb]

Rodney E. Shackelford, D.O., Ph.D.
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Cite this page: Shackelford R. Polymerase chain reaction - history. website. Accessed May 28th, 2020.
Pre-PCR history
  • Prior to PCR technology, obtaining multiple copies of a specific DNA sequence was commonly done but often laborious

  • Most protocols involved:
    1. Isolating many copies of the sequence(s) desired
    2. Cloning the DNA into a viral or bacterial plasmid vector
    3. Transfecting, selecting and growing the bacteria carrying the DNA and vector
    4. Reisolating the desired sequence(s) from bacterial cultures by purifying and cutting the plasmids

  • Limitations:
    1. Procedure could take several weeks
    2. Often difficult to get pure DNA / gene sequences from the complex mixtures typically used to obtain DNA samples
Initial discovery of PCR
  • Conceived in 1983 by Kary Mullis (Wikipedia: Kary Mullis [Accessed 4 June 2018]), working at Cetus Corporation as a chemist
  • Initial idea was to use a pair of primers to bracket the desired DNA sequence and to copy it repeatedly using DNA polymerase
  • Mullis received a $10,000 bonus from Cetus for the invention; Cetus later sold the patent to Roche for $300 million; Mullis may have received additional money for testifying on behalf of Cetus in a patent lawsuit
Later PCR related work
  • Cetus initially used PCR to detect the hemoglobin sickle cell point mutation
  • Mullis thought of using DNA polymerase from Thermophilus aquaticus (Taq, Wikipedia: Thermus aquaticus [Accessed 4 June 2018]), which was heat resistant; this eliminated the need to add enzyme after every cycle of thermal denaturation of the DNA, making the technique more affordable and subject to automation
  • Mullis won the Nobel Prize in Chemistry in 1993 for this work
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